Preparation of carbonic acid esters



Patented Feb. 21, 1945 v zsrosn raarana'non'or cannomo Aom Es'rsns Irving E. Muskat and Franklin Strain, Akron,

Ohio, assignors to Pittsburgh Plate Glass Company, Allegheny County, Pa., a corporation of Pennsylvania No Drawing. Application March as, 1941, Serial No. 385,777

8 Claims.

This invention relates to a novel method of preparing unsaturated esters of polyhydroxy alcohols and is particularly related to the production of glycol esters. These compounds have a structure represented by the following general in which R is anorganlc radical of a: valence and R1 is an organic radical such as hydrocarbon or substituted hydrocarbon radical and a: is a small whole number.

In accordance with this invention, unsaturated esters are produced by reacting an unsaturated alcohol with a polyhaloformate. The polyhaloformates of the following hydroxy compounds are suitable for the reaction: glycols or polyglycols, such as the alkylene glycols, for example, ethylene glycol, trimethylene glycol, pentamethylene glycol, tetramethylene glycol, propylene glycol or glycerol, alpha, beta methyl glycerol, or mannitol, etc.; polyhydroxy aromatic or araliph'atic compounds such as resorcinol, hydroquinone, dihydroxy diphenyl, phthalyl alcohol, dihydroxy naphthalenes, etc., or the polyhydroxy ethers, polyglycols, polyglycerols, etc. such as the di-, tri-, and tetraethylene glycols, the di-, trl-, and tetrapropylene glycols, the polybutylene glycols, the polyglycerols or substituted polyglycerols, glycerol monomethyl ether, 1,2-dihydroxy 4 ethyloxy butane, aa-dihydroxy diphenyl ether. Also, the polyhydroxy cyclic ethers such as the dioxane diols or the compounds CH=C-OH \CH=C0H (IE on on-cm-d-o--cmon and CH1 C Also, the corresponding polyhydroxy thio-ethers such as his (hydroxy ethyl) sulphide,

bis (hydroxy phenyl) sulphide (OHCsH4)2S, hydroxy ethylhydroxy phenyl thio-ether and the cyclic thio-ethers analogous to the above cyclic ethers may be treated. The chloroformates may be made by reacting the polyhydroxy compounds with phosgene, preferably at a low temperature, for example, 0 C. or below, in the manner described in copending application Serial No. 385,774 filed March 28, 1941, Case No. A-l70, for the production of dichloroformates of polyglycols.

In accordance with the invention, the chloroformates may be reacted with unsaturated alcohols containing up to 10 carbon atoms such as allyl, methallyl, crotyl, isocrotyl, tiglyl, angelyl, methyl vinyl carbinyl, ethyl allyl, citronellol, cinnamyl, geraniol, propargyl, or the higher molecular alcohols such as oleyl alcohol or linoieyl alcohol .or the halogen substituted alcohols such as 2- -chloroallyl, 2-bromoallyl, chlorocrotyl alcohol, or

S-chlorobutene-Z-l-i, etc. or the higher alcohols such as oleyl and linoleyl alcohol.

The reaction may be promoted by the presence of an alkaline reagent including organic bases such as pyridine, dimethyl aniline, and quaternary ammonium bases such as trimethyl phenyl ammonium hydroxide or the oxides, carbonates, and hydroxides of sodium, potassium, calcium, barium, strontium, magnesium and other alkali or earth alkali metals may be used. The alkaline agent may be in solution or it may be dispersed in the reaction liquid as a finely pulverized solid material. Finely divided calcium carbonate has been especially efiective. Water may be present or the reactionmay be conducted under substantially anhydrous conditions. It may, under some conditions, be desirable to add diluents such as water, acetone, benzene, carbon tetrachloride or dioxane.

The reaction temperature may be maintained at normal room temperature (15-25 C.). Frequently, however, higher or lower temperatures may be used, depending upon the nature of the vention are generally liquids but may, in some cases, be solids at normal temperatures. They are usually miscible in acetone, benzene, ethyl alcohol and dioxane and have utility as solvents for many organic plastics such as vinyl acetate,

Example I To a mixture of 150 g. of allyl alcohol and 187 g. of ethylene glycol bis (chloroformate) was added slowly with stirring 200 g. of cold 50% aqueous sodium hydroxide, keeping the temperature at allyl alcohol over the stoichlometric amount and with 150% excess of finely divided calcium carbonate in. a three-necked flask equipped with stirrer and reflux condenser. The mixture was heated for 13 minutes between 85-l20 C. and subsequently for '75 minutes between 120 C. and 125 C. The product was washed with very dilute hydrochloric ,acid and heated to 115 C. while -5 C. 'The reaction mixture was diluted with water and the oily ester separated and distilled. Colorles glycol his (aim carbonate) B. P., 130- 140 C. at 1-2 mm. pressure was obtained.

Example II The process 0! Example I was repeated usin an equivalent quantity of 2-chloroallyl alcohol in lieu of allyl alcohoiand the corresponding ether glycol bis (2-chloroallyl carbonate) was obtained.

Example 11! Five moles (935 gms.) of distilled ethylene glycol bis (chloroformate) was added slowly to a mixture of 929 cc. of methallyl alcohol excess) and 954 cc. of pyridine excess). The

- addition was made at a rate oi. 1.5 moles per hour and the temperature maintained at about 5 C. After the reaction mixture had been permitted to warm to room temperature it was diluted with water. The ester was washed successively with 5% sulphuric acid, 5% caustic soda and water. It was decolorlzed with charcoal by heating at 80- 100 C. while evacuating at 15 mm. to remove methallyl alcohol. 915 gms. of ethylene bis (methallyl carbonate) were collected between 135 and 145 C. by distillation at a pressure of 3 mm.

Example IV A75 gm. sample of ethylene glycol bis (chloroformate) was mixed with 1.2 moles of methallyl alcohol representing 150% of the theoretical requirements for complete esteriflcation. The mixture was placed in a three-necked flask equipped with stirring device, thermometer and reflux condenser. A slight excess (5%) of 50% NaOH was added slowly over a period 01' 81 minutes. The reaction vessel was maintained at a temperature between 5 and 0 C. by artificial cooling. After the mixing was completed, the mixture was stirred for minutes at a temperature between 4 and 7 C. The ethylene glycol bis (methallyl carbonate) was purifled by distillation at 2 mm. pressure. .4 yield of 53% was obtained.

E's-ample V A 75 gm. sample of ethylene glycol bis (chloroformate) was mixed with 150% excess oi methpassing a stream of CO: through the mixture. This procedure caused the separation of the unreacted methallyl alcohol. The mixture was then distilled under vacuum ata total pressure of 2 mm. 70.4 gms. of ethylene glycol bis (methallyl carbonate) was collected between 138 and 144 C.

Although the present invention has been described with reference to the speciflc details of certain embodiments thereof, it is not intended that such details shall be regarded as limitations upon the scope of the invention except insofar as included in the accompanying claims.

This application is a continuation-in-part of copending application Serial No. 361,280, flied October 15, 1940.

We claim:

1. The method of preparing glycol bis (unsaturated alcohol carbonate) which comprises reacting a glycol bis chloroformate with an unsaturated monohydric alcohol.

2. The method of preparing ethylene glycol bis -(unsaturated alcohol carbonate) which comprises (ailyl carbonate) which comprises reacting ethylene glycol bis chloroformate with allyl alcohol.

4. The method of preparing ethylene glycol bis (chlorallyl carbonate) which comprises reacting ethylene glycol bis chloroformate with chloroallyl alcohol.

5. The method of preparing ethylene glycol bis (methallyl carbonate) which comprises reacting ethylene glycol bis chloroformate with methallyl alcohol.

6. The method of claim 2 in which the unsaturated alcohol is one of a group consisting of the prophenols, butenols, and pentenols.

'l. The method of preparing a glycol bis (unsaturated alcohol carbonate) by reacting a glycol dichloroformate with a monohydric unsaturated alcohol in the presence of an alkaline reagent. I

8. The method 01'. preparing ethylene glycol bis (unsaturated alcohol carbonate) by reacting ethylene glycol dichloroi'ormate with a monohydric unsaturatedalcohol in th presence of finely divided calcium carbonate at a temperature above IRVING E. MUSKAT. msnmm STRAIN. 

